Field of the Invention
The present invention relates to a method of manufacturing a semiconductor device and a semiconductor device, and can be suitably utilized, for example, for a semiconductor device including a contact portion with a semiconductor substrate and a contact portion with a metal silicide film.
Description of the Background Art
Some semiconductor devices include a substrate contact portion formed therein for fixing a semiconductor substrate (silicon) at a prescribed potential. In such a semiconductor device, a plurality of element formation regions are defined by an element isolation region, with the substrate contact portion disposed outside the element formation regions. This type of semiconductor device is disclosed in Patent Document 1 (Japanese Patent Laying-Open No. 2013-222838) and Patent Document 2 (Japanese Patent Laying-Open No. 2015-37099).
In the element formation regions, prescribed semiconductor elements such as a CMOS (Complementary Metal Oxide Semiconductor) transistor, a high breakdown voltage NMOS transistor and a high breakdown voltage PMOS transistor are formed. A metal silicide film is formed on source/drain regions and a gate electrode of each of the transistors such as the CMOS transistor.
An interlayer insulating film is formed to cover those semiconductor elements. A plurality of wires are formed on the surface of the interlayer insulating film. A predetermined one of the plurality of wires is electrically connected to the semiconductor substrate through the substrate contact portion. Another predetermined one of the plurality of wires is electrically connected to the metal silicide film of each semiconductor element through an element contact portion.
In the substrate contact portion, a plug is formed in a relatively deep contact hole extending from the surface of the interlayer insulating film and reaching the semiconductor substrate, with a barrier metal film interposed therebetween. In the element contact portion, a plug is formed in a relatively shallow contact hole extending from the surface of the interlayer insulating film and reaching the metal silicide film, with a barrier metal film interposed therebetween.
When forming the barrier metal film of the substrate contact portion, the barrier metal film is formed without carrying out pretreatment (reverse sputtering) on the deep contact hole. In contrast, when forming the barrier metal film of the element contact portion, the barrier metal film is formed after carrying out pretreatment on the shallow contact hole over the metal silicide film.